Polymer adjuvants for innate and cellular based vaccination

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In the early days of commercial vaccine manufacture, significant variation between the effectiveness of different batches of the same vaccine were correctly ascribed to contamination of the reaction vessels. However, more scrupulous attention to cleanliness seemed to reduce the effectiveness of the vaccines, suggesting the contaminants actually enhanced immunogenicity. These contaminants were described as 'adjuvants'; agents which stimulate the immune system and increase the response to a vaccine, without having any intrinsic antigenic effect. They do this by creating a non-specific pro-inflammatory environment, where presentation of specific antigens leading to a vaccine response is much more efficient. Experience shows that adjuvants make a crucial contribution to the development of effective vaccines, and many adjuvants are now in widespread use, including oils, aluminium salts and virosomes.The field of vaccination is of ever-increasing importance, ranging from successful eradication of Smallpox in 1977 (estimated to have saved 30 m lives) through to the pressing need for prophylactic (and ideally therapeutic) vaccines for HIV, malaria, TB and cancer. New adjuvants will make an important contribution to the development of new vaccines, as some of the most effective adjuvants to date (such as Freund's adjuvants) cannot be manufactured to cGMP and are not suitable for clinical use. One way to address this shortfall is to design and produce potent and specific synthetic molecular adjuvants which are suitable for cGMP manufacture.We will synthesize polymer-TLR ligands conjugates which are capable of binding their receptor and activate a programmed cytokine response. Multivalent reactive polymers will be synthesized using controlled radical polymerization to obtain polymers which have a narrow molecular weight distribution. Hydrophilic monomers such as polyethylene glycol methacrylate, or N,(2-hydroxypropylmethacrylamide) will be co-polymerized with either an activated ester bearing monomer or an azide bearing monomer for subsequent modification. Three parameters of polymer structure will be examined in order to determine optimum capacity of the materials to induce an immune response: Firstly the molecular weight and polydispersity of the polymer; secondly the number of TLR ligands per polymer and finally the spacer length and properties. All of these parameters will be adjusted in parallel and are important in understanding how features of the material alter the immune response.Biological activity will be initially assessed using reporter cells which are activated upon stimulation of any TLR ligands. A reporter protein is expressed and reflects the level of activation of the cells and thus an indicator of stimulation. Secondly, the specific activity of the ligand-polymer conjugates will be assessed to determine whether the materials stimulate either a cell based or antibody based immune response by measuring the relative quantities of the cytokines released following activation.